What's really worth paying to see in Rapid City, SD?

The airplane museum at Ellsworth AFB just next door to Rapid in Box Elder. If you are going to be around at Sturgis time, just day trip to Sturgis, check out the sites, be sure to look in the front windows of the "ink artists" (tat parlors)as some do the artistry directly in the window. Play golf at the Elks Lodge course and visit all the pre-mentioned sites.